debcrafters-packages team mailing list archive

[Pjfloyd <1247026@xxxxxxxxxxxxxxxxxx>]

(In reply to Matt from comment #9)

>  It does expose an issue on Ubuntu/Debian 64 bit machines and maybe others. 
> Is it reasonable to have no entry point for strlen(),  which is an ANSI C
> library function? 
 
> It would certainly be 'easier' in some sense if valgrind moved to another
> means of detecting a library with proper debug symbols.

I don't think that you understand the problem.

Valgrind (and in particular, memcheck) is running and checking the guest
binary from the get go. That means that everything runs under Valgrind,
including the code for ld.so that loads any shared libraries like
libc.so. Because libc.so isn't even loaded yet when ld.so is doing its
stuff ld.so also provides its own implementation of a few libc functions
like malloc and strlen.  Some platforms have optimised versions of
strlen that generate many false positives. We need to redirect strlen to
avoid them and so strlen redirection is mandatory.

The only other thing that I could do is to make this a configure time
check. That way packagers could turn off the requirement. Obviously if
the distro ignores our instructions in README_PACKAGERS and ld.so strlen
needs to be redirected and Valgrind allows it to be not redirected then
you will have an unusable Valgrind.

-- 
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https://bugs.launchpad.net/bugs/1247026

Title:
  valgrind does not work on amd64 (strlen missing)

Status in Valgrind:
  Unknown
Status in glibc package in Ubuntu:
  Confirmed
Status in valgrind package in Ubuntu:
  Confirmed

Bug description:
  It seems that strlen has been inlined in the amd64 version of glibc
  currently used in Ubuntu 13.10 (saucy). This makes it impossible to
  run valgrind. It fails with the following output:

  valgrind:  Fatal error at startup: a function redirection
  valgrind:  which is mandatory for this platform-tool combination
  valgrind:  cannot be set up.  Details of the redirection are:
  valgrind:  
  valgrind:  A must-be-redirected function
  valgrind:  whose name matches the pattern:      strlen
  valgrind:  in an object with soname matching:   ld-linux-x86-64.so.2
  valgrind:  was not found whilst processing
  valgrind:  symbols from the object with soname: ld-linux-x86-64.so.2
  valgrind:  
  valgrind:  Possible fixes: (1, short term): install glibc's debuginfo
  valgrind:  package on this machine.  (2, longer term): ask the packagers
  valgrind:  for your Linux distribution to please in future ship a non-
  valgrind:  stripped ld.so (or whatever the dynamic linker .so is called)
  valgrind:  that exports the above-named function using the standard
  valgrind:  calling conventions for this platform.  The package you need
  valgrind:  to install for fix (1) is called
  valgrind:  
  valgrind:    On Debian, Ubuntu:                 libc6-dbg
  valgrind:    On SuSE, openSuSE, Fedora, RHEL:   glibc-debuginfo
  valgrind:  
  valgrind:  Cannot continue -- exiting now.  Sorry.

  Either the glibc package needs to be fixed so it does not inline
  strlen or valgrind needs to be fixed. A work-around patch to valgrind
  can be found in this thread:
  https://bugs.kde.org/show_bug.cgi?id=286864

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